The present invention pertains to a device for controlling auxiliary means, such as plunger ejector needles, strippers, etc., arranged in the reciprocating carriage of single- or multistage presses.
It is known in the art to control such auxiliary means which are moved back and forth with the press carriage over a crank drive, by means of a stationary curved track directly by the carriage movement. The disadvantage of such a device is that control depends necessarily on the movement of the carriage. Due to the stationary arrangement of the curved track, the sequence of motions during the forward and backward run is the same related to the front dead center. If the auxiliary means to be controlled is a plunger ejector needle, for example, the ejection time in this device must be placed in the rear dead center range in order to avoid pressure on the needle receding only during the advance of the carriage.
For a multistage press, it is furthermore known to use a control device where the ejecting means consists of two-arm levers which are mounted in an oscillating plunger holder. The two-arm levers, of which one is provided for each stage, are actuated by a control mechanism arranged in the machine body or press frame. Since both the carriage movement and the pivotal movement of the plunger holder must be considered in the control, this type of control is rather complicated. Besides the resulting additional loads of the plunger holder requires a stronger support. This results, however, in inertia forces, which is undesired, particularly in high-speed machines.